6 times 12 is 72 so 14 times 12 would be 168 if that is what you are looking for. So for that y=168 :-)
We know, cos A + cos B = 2cos(C+D)/2 × cos(C - D)/2
So,
cos 130 + cos 110 + cos 10
cos 130 + 2cos (110+10)/2 × cos( 110-10)/2
cos 130 + 2cos 60 × cos 50
cos ( 180 - 50 ) + 2cos60 cos 50
We know, cos ( 180 - A ) = -cos A
2cos 60 cos 50 - cos 50
Also, cos 60 = 0.5
2×0.5 cos 50 - cos50
cos 50 - cos 50
0 = RHS.
Hence proved
A graph has a constant rate of change when the graph is linear and portrays a straight line. The slope will remain constant which forms the straight line in the graph.
Center of the circle is (5; -5)
